Synergistic Modification for Efficient Perovskite Solar Cells with Small Voltage Loss

The power conversion efficiency (PCE) of perovskite solar cells has improved quickly in the past few years, but the PCE is still much lower than the theoretical limit. The relatively high energy loss (E_loss) is one of the critical factors limiting the PCE. To resolve the above issues, a synergistic modification strategy was used herein to minimize E_loss. RbCl and potassium polyacrylate (K-PAM) were used to modify the SnO₂ layer. Additionally, Pb(Ac)₂ was introduced into PbI₂ to further improve the film quality. The synergistic modification strategy reduced the defects in SnO₂ and perovskite and improved the energy-level alignment, enabling significantly reduced E_loss and enhanced photovoltaic performance. The best PCE of 24.07% was achieved, which was much higher than that of the control device (20.86%). The E_loss was only 0.349 eV for the target device. Good stability was achieved for the cells made using modified SnO₂ and perovskite layers.